//const修饰指针
int main()
{
    int a = 135, b = 255;
    const int *p = &a;
    p = &b;
    //*p = 21;
    int const *q = &b;
    q = &a;
    //*q = 15;
    int *const e = &a;
    //e = &b;
    *e = 45;
    
    return 0;
}